Stethoscope.



lPATEIITBD JAN.. 3, 1905.

II. G. A. I. WIEDER.

STETHOSCOPE.

APPLICATION FILED ums, 1903.

UNITED STATES Patented January 3, 1905.

PATENT OEEICE.

STETHOSCOFE.

SPECIFICATION forming part of Letters Patent No. 779,144, dated January 3, 1905.

Application tiled December 3,1903. Serial No. 183,679.

To ir/ZZ whore it nto/y concern:

Be it known that I, HENRY GEORGE ABRA- HAM IsAAe WIEDER, a subject of the Emperor ot' Austria-Hungary, and a resident ot' 6 White Lion street, Bishopsgate, London, in the county of Middlesex, England, have invented new and useful Improvements in Stethoscopes and other Instruments for Rendering Teak Sounds Distinctly Audible, or' which the following is a specification.

My invention relates to stethoscopes or instruments for rendering easily audible weak sounds in the human body or to instruments of similar kind, such as ear-trumpets vand the like, used for rendering more audible other sounds in which a diaphragm caused to vibrate by the sounds is used; and the objects of my invention are, tirst, to provide means by which the diaphragm is highly stretched and rendered very tense and sensitive; second, to collect and direct upon the diaphragm the sound-Vibrations received, and, third, to prevent the interference of extraneous sounds with those received and reproduced by the instrument. I attain these objects by the means illustrated in the accompanying drawings, in which- Figure l is a section through the center ot` the instrument, and Eig. 2 is a view from the back.

(t is a very thin circular disk or diaphragm, of metal or other suitable material, the edge of which is iitted into the inner edge of a cylindrical ring ot' brass or other metal or material.

c is an outercylindrical case, of ebonite or other like suitable material, having a cylindrical recess at d, into which the ring I) and diaphragm a iit and are inserted, resting against a narrow shoulder at CZ on the inner side ot' the case c. Inside the ring is litted acircular flat plate e, of metal or other hard material, having a small slightlyprojecting rim round its upper edge at f, which when inserted in its place presses against and holds the edge of the ring I) and diaphragm c, giving the latter a very rigid tension and leaving a very narrow space at g between it and the face of the plate e, which has also an outer flange, the edge `of which is level with the outer edge of the ring 7), both being some distance inside the outer edge ot' the fiange ot' the case c, which is screwed inside with a tine thread to receive a corresponding ring t, the outer edge of which is milled at a', so that it can be readily screwed in with the lingers to tix the ring and diaphragm c or unscrewed when required.

The back ol the plate a has at its center a projecting tubular boss j, upon which can be screwed a. junction piece f, having two branches I Z', to which flexible tubes can be easily attached and brought to the ears of the listener.

In order to obtain the highest efficiency, the central part of the diaphragm a must be rendered quite rigid and incapable ot' independent vibration and only the part between such rigid center and the edge must communicate its Vibrations to the air in the space between the diaphragm a and the plate c.

In order to insure the perfect rigidity ot' the central part oi' the diaphragm c, upon which is fitted the open wide end otl the thin metal cone fm, upon the apex of which is lixed the smaller inverted cone a, a slightly curved or arched metal disk p is arranged across the back ot' the diaphragm c, against which itcan be tightened with any desired force by a central bolt q, the enlarged cylindrical head ot' which, r, lits into the bottom of the small cone n, through which it passes, while its top w' is curved or spherical in shape. The cone m distributes the sound-waves equally all round the diaphragm, while the top receives the sound.

The bolt 4f/ passes centrally through the cones m and ln, the diaphragm c, and the curved disk p, which latter is forced up by tightening the nut ,s (through the opening in the boss j) until the center ot' the diaphragm c is drawn up into the mouth of the cone m, as shown, by the curved disk 71, the said central part being thus made rigid and non-vibrating and the loudness and clearness ot' the sounds produced by the instrument being' enormously increased. This arrangement is essential to the perfect working of the instrument.

The spherical top 1" ot' the bolt q projects slightly beyond the edge of the cone nf, which IOC) ,without inconvenience.

is pressed gently upon the surface-such as the human breast-the sound from or near which is to be transmitted through the tubes Z Z to the ear of the listener.

The outer part of the case c is formed as a cone fa, the small open end of which surrounds freely the small cone a and the bolt-head This outer cone u forms a perfect protection to the diaphragm and to the two cones, while occupying very little space. It also serves to protect the diaphragm from any sound or noise going on outside the sphere of the sounds which it is desired to hear, so that it is possible to hear the desired noises very distinctly, but not other noises which are continually going on around.

For greater convenience and comfort I make a ring of soft india-rubber or the like material and of suitable shape, upon the outer edge of the cone a of the ease, which can be pressed into more close contact with the body For some medical or other purposes, such as `for stethoseopes, the spherical top o" of the bolt q (or a suflciently long rigid projecting' rod, which may be screwed upon it or form part of it) and the edge of the small cone fn are held against or near the position of origin of the sound to be magnified-as, for instance, the chest, opposite the heart or lungs-andthe outer end of the flexible tubes (or of one of them) are held in the ears, (or ear.)

The whole apparatus is purely mechanical,

there being no magnet of any kind nor any electricity used.

I am aware that instruments have been made in which the center of the diaphragm a is provided with a rigid cone, such as m., haring an inverted cone, such as fn, on its summit, and I do not, therefore, claim such a combination broadly; but

That I claim, and desire to secure by Letters Patent, is

l. The combination of the diaphragm a, ring outer case c, recess (l, screwed ring t, plate e, hollow boss j', cone mi, inverted cone or, curved disk 22, bolt 0, cylindrical rounded head v', and nut s, all substantially as set forth.

2. The combination of a thin diaphragm ft rigidly held at its outer edge, a hollow cone a litting against the center of the outer side of the diaphragm, a curved disk j; litting against the inner side of the diaphragm (l, a central bolt q passing' through the center of the cone m, the diaphragm u. and the curved disk p, a cylindrical head having a rounded top r en the outer end of the bolt, and a screwed nut 1- at the inner end of the bolt, all substantiallyv as set forth.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

HENRY GEORGE AllllAllAlll lSAAC WlEllEll` Witnesses:

ALFRED T. BRA'r'roN, H. D. JAMESON. 

